Ignition circuit radiation suppression resistor

ABSTRACT

A wire resistor including a ceramic core and a resistor wire wrapped on the core constructed of approximately 4.5 percent aluminum, 22 percent chromium, 0.5 percent cobalt and the balance iron, which is coated with an insulating material, is positioned between an internal combustion engine ignition circuit spark plug lead and the associated spark plug for suppressing electromagnetic radiation on firing of the spark plug in the frequency range of 20-1,000 megahertz to prevent pollution of the air by extraneous radiation.

United States Patent Berry Field of Search IGNITION CIRCUIT RADIATIONSUPPRESSION RESISTOR lnventor: Norman H. Berry, 49 Cambridge, PleasantRidge, Mich. 48069 Filed: Dec. 16, 1970 Appl. No.: 98,604

US. Cl. ..338/334, 123/148 A, 174/355 M, 252/513, 338/66, 338/270 Int.Cl .1101: 1/06 ..338/66, 267-270, 338/264, 301, 302, 334; 174/355 M, 36;123/148 A, 148 P; 252/513; 330/177 References Cited UNITED STATESPATENTS 7 58,439 10/ 1 866 l y o n 23 6017 lGNITlON CIRCUIT lllllll [4 1July 25,1972

Houchin ..l36/l77 3,191,132 6/1965 Mayer 174/36 3,212,044 10/1965 Cloud3,529,273 9/1970 Morris ..338/66 Primary Examiner-E. A. GoldbergAnorneyWhittemore, l-lulbert & Belknap [57] ABSTRACT 9 Claims, 1 DrawingFigure APPROXIMATE WIRE COMPOSITION 4.5% ALUMINUM 22 CHROMIUM 5% COBALTBALANCE IRON PAIENIEHIIII2 Am 3.680.029

IGNITION CIRCUIT /I6 I I I I I I I APPROXIMATE wIRE COMPOSITION 4.5%ALUMINUM 22 CHROMIUM 5% COBALT 24 BALANCE IRoN INVENTOR NORMAN H. BERRYBY ;LZ TE,-E-

BACKGROUND OF THE INVENTION 1. Field of the Invention The inventionrelates to ignition circuits of the type used on automobiles and refersmore specifically to a wire wound resistor including a substantialamount of iron in the resistor wire for suppressing extraneouselectromagnetic radiation produced on firing of the spark plugs, whichsuppression is enhanced due to the hysteresis effect of the iron in theresistor wire.

2. Description of the Prior Art Relatively recently, ecologists havediscovered pollution of the airwaves in certain areas by electromagneticwaves which are not dissipated or confined in the area of use thereof.Thus, for example, garage doors may open and close for no apparentreason in areas where a large number of automobiles are operated,communication may be interrupted with satellites and navigational gearmay mysteriously indicate incorrect directions. Such malfunctioning dueto electromagnetic interference of our airwaves may be particularlyexpensive and sometimes dangerous.

Thus, for example, in a newly built lnternal Revenue Service complex inLouisiana, part of the computers memory suddenly went blank, and it wassubsequently discovered that signals from the New Orleans airport erasedthe tax records that had been freshly stored on the computers electronictape. Also, certain pacemakers for the heart designed to steady the beatof a faltering heart can be knocked temporarily out of rhythm if theyhappen to come close to microwave ovens.

The Federal Communications Commission has therefore attempted toregulate the use of the airwaves and has provided standards forelectronic radiation control. The Society of Automotive Engineers(S.A.E.) have recommended one such regulation in S.A.E. Standard J55la,stating maximum permissible radiation from automobile ignition circuitson firing of the spark plugs therein.

Standard original equipment automobile ignition circuits maintain theiremission below the maximum recommended by the S.A.E. at the testingrequired by the S.A.E. Standard J55la. Such original equipment generallyincludes a nonmetallic carbon impregnated nylon core spark plug lead.Replacement spark plug leads, however, have generally been of theinsulated wire type. For example, copper wire has been used. The solidwire spark plug leads radiate substantial energy on firing of the sparkplugs if the energy is not suppressed.

In the past resistors have been placed between the spark plugs and sparkplug leads to suppress passage of energy from the spark plugs to theleads on firing of the spark plugs. Also, the spark plug leads havesometimes in the past been wrapped with monel coils to suppress theradiation from the spark plug leads on firing of the spark plugs. Suchradiation suppression means have been effective in after-market sparkplug leads to reduce radiation from the spark plug leads to within theprescribed S.A.E. limits at lower frequencies. However, at higherfrequency in the band indicated above the radiation permitted by thesedevices has in the past been at or slightly over the maximum recommendedby S.A.E. Standard J55la. It is desirable to reduce the radiation fromthe after-market spark plug leads to a radiation no greater than thatprovided by the original equipment manufacturers in the frequency rangefrom 20MH to l,000MH,

SUMMARY OF THE INVENTION To further reduce the emission from solid wirespark plug leads, there is therefore provided in accordance with theinvention a resistor between the spark plug and spark plug lead which isa wire wound resistor on an insulating core. The wire wound resistor hasa substantial iron content so that the electromagnetic energy producedon firing of the park plugs will be dissipated in the resistor partlydue to the hysteresis efiect of the iron in the resistor along with theusual attenuation of the radiation due to the alternating and directcurrent resistance provided by the resistor.

BRIEF DESCRIPTION OF THE DRAWINGS spark plug lead and a spark plug in anautomobile ignition circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the FIGURE, a wirewound resistor 10 is connected between a spark plug lead 12 and a sparkplug 14 in a usual internal combustion engine ignition circuit 16.

In accordance with the usual operation of the ignition circuit 16, thespark plug 14 is periodically caused to discharge, whereby alternatingsignals over the entire frequency range of, for example, from 20-l,OOOMH, may be created which if pased back to the spark plug lead wire12 will be radiated a substantial distance from the ignition circuit tocause radiation pollution of the airwaves.

The wire wound resistor 10 includes a core 18 of high temperatureresistant material such as a ceramic and a resistor wire coil 20 woundon the core 18. Metal connectors 22 and 24 are provided, as shown, toconnect the wire of the wire wound resistor 10 to the spark plug lead 12at one end and to the spark plug 14 at the other end.

The electrical energy created on firing of the spark plug 14 isdissipated in the resistor 10 due to the impedance of the wire 20 to thefrequency of the signals produced on firing of the spark plug 14 and thedirect current resistance of the material of which the wire 20 isconstructed.

In addition and in accordance with the invention, the alternating energyproduced on firing of the spark plug 14 is further attenuated beforearriving at the spark plug lead 12 by the hysteresis effect of theparticular resistor wire 20. Resistor wire 20 contains a substantialamount of iron to provide the hysteresis eifect which further attenuatesthe alternating energy created by the spark plug 14.

The wire 20 is relatively thin and may be between 0.001 and 0.0015inches in diameter and approximately 18 feet long and include amounts ofchromium, aluminum and cobalt to provide required direct currentresistance which a pure iron wire would provide very littleof.

In one example, the wire 20 wound on a ceramic core one eighth inch indiameter and three fourth inch inch long was 0.0015 inches in diameterand had a composition of approximately 4.5 percent aluminum, 22 percentchromium, 0.5 percent cobalt and the balance was iron by weight.

The energy absorption due to the hysteresis of the iron in the coil,which hysteresis is defined as the magnetization of a sample of iron dueto a magnetic field which is made to vary through a cycle of values andlags behind the magnetic field. Standard textbooks provide an equationdeveloped by Steinmetz for hysteresis and give the law of energy in ergsper cycle per centimeter cubed which may be dissipated by the hysteresiseffect as:

where B is the maximum induction in maxwells per cm and n is thecoefficient of hysteresis.

While as noted above a pure iron resistor wire will provide a -minimumof direct current-resistance of approximately 3000 While one embodimentof the invention has been considered in detail, it will be understoodthat other modifications and embodiments are contemplated by theinventor. It is intended to include all modifications and embodiments asare defined by the appended claims within the scope of the invention.

What I Claim as my invention is:

l. A resistor for use in automobile ignition spark plug circuits or thelike comprising a ceramic insulating core, a wire coil wound on theinsulating core having a substantial iron content whereby energy isdissipated in the resistor due to the hysteresis effect of the ironcontent thereof and insulating material applied to the wire coil andceramic core.

2. Structure as set forth in claim 1 wherein the wire is approximately4.5 percent aluminum, 22 percent chromium, 0.5 percent cobalt and thebalance iron.

3. Structure as set forth in claim 1 wherein the resistor wire isapproximately 70 percent iron.

4. Structure as set forth in claim 1 wherein the wire is approximately0.0015 inches in diameter.

5. Structure as set forth in claim 1 wherein the resistor wire isapproximately 18 feet long.

6. A resistor for use in automobile ignition spark plug circuits or thelike comprising an insulating core and a wire coil wound on theinsulating core, the wire of which is approximately 4.5 percentaluminum, 22 percent chromium, 0.5 percent cobalt and the balance iron,whereby energy is dissipated in the resistor due to the hysteresiseffect of the iron content thereof.

7. Structure as set forth in claim 6 wherein the resistor wire isapproximately 0.0015 inches in diameter.

8. Structure as set forth in claim 6 wherein the resistor wire isapproximately 18 feet long.

9. In combination in an ignition system, a spark plug lead, a spark plugand a wire wound resistor in series between the spark plug and the sparkplug lead immediately adjacent the spark plug for suppressing radiationon firing of the spark plug which resistor includes a ceramic core and awire coil wound on the ceramic core including a substantial amount ofiron whereby alternating energy created by the spark plugs in the rangeof 20-l,000 megahertz, in addition to that dissipated due to theresistance value of the resistor, is dissipated due to the hysteresiseffect of the iron in the resistor coil.

1. l i l

2. Structure as set forth in claim 1 wherein the wire is approximately4.5 percent aluminum, 22 percent chromium, 0.5 percent cobalt and thebalance iron.
 3. Structure as set forth in claim 1 wherein the resistorwire is approximately 70 percent iron.
 4. Structure as set forth inclaim 1 wherein the wire is approximately 0.0015 inches in diameter. 5.Structure as set forth in claim 1 wherein the resistor wire isapproximately 18 feet long.
 6. A resistor for use in automobile ignitionspark plug circuits or the like comprising an insulating core and a wirecoil wound on the insulating core, the wire of which is approximately4.5 percent aluminum, 22 percent chromium, 0.5 percent cobalt and thebalance iron, whereby energy is dissipated in the resistor due to thehysteresis effect of the iron content thereof.
 7. Structure as set forthin claim 6 wherein the resistor wire is approximately 0.0015 inches indiameter.
 8. Structure as set forth in claim 6 wherein the resistor wireis approximately 18 feet long.
 9. In combination in an ignition system,a spark plug lead, a spark plug and a wire wound resistor in seriesbetween the spark plug and the spark plug lead immediately adjacent thespark plug for suppressing radiation on firing of the spark plug whichresistor includes a ceramic core and a wire coil wound on the ceramiccore including a substantial amount of iron whereby alternating energycreated by the spark plugs in the range of 20-1,000 megahertz, inaddition to that dissipated due to the resistance value of the resistor,is dissipated due to the hysteresis effect of the iron in the resistorcoil.